This invention represents an improvement over that disclosed in U.S. Pat. No. 3,923,407 issued Dec. 3, 1975, to L. B. Jensen and R. E. Thune. The invention disclosed therein functions quite well from a structural standpoint. That is, the locking ring securely holds the upper works to the car body or lower works and yet permits separation and reattachment, i.e. undecking and decking, without affecting any of the torqued bolt connections in the turntable assembly.
It has been found that the locking ring, especially at that point diametrically opposite the actuating cylinder, i.e. the heel of the locking ring, is difficult to seat completely. A complete peripheral seating between the locking ring and the facing groove is important in order to achieve the proper strength in this connection. Complete seating is achieved with the structural arrangement in the aforementioned patent by shifting the weight of the crane upper around the turntable. This was done through adjustments to the sling members suspending the crane upper from a helper crane. This variation changed the location of maximum frictional forces and deflections resulting from the weight of the upper being imposed on the lower. The shifting of the weight caused the locking ring to thereby "work" into its properly fully seated position in which it engages the groove provided on one of the bearing races in the turntable. This process, while effective, was cumbersome and time consuming.
The present invention provides a means for initially seating the locking ring, eliminates the need for "working" the locking ring into position, simplifies the reattachment procedure and accomplishes the reattachment faster and with greater assurance.